/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "IPCBlobInputStreamThread.h"

#include "mozilla/StaticMutex.h"

#include "mozilla/SystemGroup.h"

#include "mozilla/TaskCategory.h"

#include "mozilla/ipc/BackgroundChild.h"

#include "mozilla/ipc/PBackgroundChild.h"

#include "nsXPCOMPrivate.h"

namespace mozilla {

using namespace ipc;

namespace dom {

namespace {

StaticMutex gIPCBlobThreadMutex;

StaticRefPtr<IPCBlobInputStreamThread> gIPCBlobThread;

bool gShutdownHasStarted = false;

class ThreadInitializeRunnable final : public Runnable

{

public:

  ThreadInitializeRunnable() : Runnable("dom::ThreadInitializeRunnable") {}

  NS_IMETHOD

  Run() override

  {

     mozilla::StaticMutexAutoLock lock(gIPCBlobThreadMutex);

     MOZ_ASSERT(gIPCBlobThread);

     gIPCBlobThread->InitializeOnMainThread();

     return NS_OK;

  }

};

class MigrateActorRunnable final : public Runnable

{

public:

  explicit MigrateActorRunnable(IPCBlobInputStreamChild* aActor)

    : Runnable("dom::MigrateActorRunnable")

    , mActor(aActor)

  {

    MOZ_ASSERT(mActor);

  }

  NS_IMETHOD

  Run() override

  {

    MOZ_ASSERT(mActor->State() == IPCBlobInputStreamChild::eInactiveMigrating);

    PBackgroundChild* actorChild =

      BackgroundChild::GetOrCreateForCurrentThread();

    if (!actorChild) {

      return NS_OK;

    }

    if (actorChild->SendPIPCBlobInputStreamConstructor(mActor, mActor->ID(),

                                                       mActor->Size())) {

      // We need manually to increase the reference for this actor because the

      // IPC allocator method is not triggered. The Release() is called by IPDL

      // when the actor is deleted.

      mActor.get()->AddRef();

      mActor->Migrated();

    }

    return NS_OK;

  }

private:

  ~MigrateActorRunnable() = default;

  RefPtr<IPCBlobInputStreamChild> mActor;

};

} // anonymous

NS_IMPL_ISUPPORTS(IPCBlobInputStreamThread, nsIObserver, nsIEventTarget)

/* static */ bool

IPCBlobInputStreamThread::IsOnFileEventTarget(nsIEventTarget* aEventTarget)

{

  MOZ_ASSERT(aEventTarget);

  mozilla::StaticMutexAutoLock lock(gIPCBlobThreadMutex);

  return gIPCBlobThread && aEventTarget == gIPCBlobThread->mThread;

}

/* static */ IPCBlobInputStreamThread*

IPCBlobInputStreamThread::GetOrCreate()

{

  mozilla::StaticMutexAutoLock lock(gIPCBlobThreadMutex);

  if (gShutdownHasStarted) {

    return nullptr;

  }

  if (!gIPCBlobThread) {

    gIPCBlobThread = new IPCBlobInputStreamThread();

    if (!gIPCBlobThread->Initialize()) {

      return nullptr;

    }

  }

  return gIPCBlobThread;

}

bool

IPCBlobInputStreamThread::Initialize()

{

  nsCOMPtr<nsIThread> thread;

  nsresult rv = NS_NewNamedThread("DOM File", getter_AddRefs(thread));

  if (NS_WARN_IF(NS_FAILED(rv))) {

    return false;

  }

  mThread = thread;

  if (!mPendingActors.IsEmpty()) {

    for (uint32_t i = 0; i < mPendingActors.Length(); ++i) {

      MigrateActorInternal(mPendingActors[i]);

    }

    mPendingActors.Clear();

  }

  if (!NS_IsMainThread()) {

    RefPtr<Runnable> runnable = new ThreadInitializeRunnable();

    SystemGroup::Dispatch(TaskCategory::Other, runnable.forget());

    return true;

  }

  InitializeOnMainThread();

  return true;

}

void

IPCBlobInputStreamThread::InitializeOnMainThread()

{

  MOZ_ASSERT(NS_IsMainThread());

  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();

  if (NS_WARN_IF(!obs)) {

    return;

  }

  nsresult rv =

    obs->AddObserver(this, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID, false);

  if (NS_WARN_IF(NS_FAILED(rv))) {

    return;

  }

}

NS_IMETHODIMP

IPCBlobInputStreamThread::Observe(nsISupports* aSubject,

                                  const char* aTopic,

                                  const char16_t* aData)

{

  MOZ_ASSERT(!strcmp(aTopic, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID));

  mozilla::StaticMutexAutoLock lock(gIPCBlobThreadMutex);

  if (mThread) {

    mThread->Shutdown();

    mThread = nullptr;

  }

  gShutdownHasStarted = true;

  gIPCBlobThread = nullptr;

  return NS_OK;

}

void

IPCBlobInputStreamThread::MigrateActor(IPCBlobInputStreamChild* aActor)

{

  MOZ_ASSERT(aActor->State() == IPCBlobInputStreamChild::eInactiveMigrating);

  mozilla::StaticMutexAutoLock lock(gIPCBlobThreadMutex);

  if (gShutdownHasStarted) {

    return;

  }

  if (!mThread) {

    // The thread is not initialized yet.

    mPendingActors.AppendElement(aActor);

    return;

  }

  MigrateActorInternal(aActor);

}

void

IPCBlobInputStreamThread::MigrateActorInternal(IPCBlobInputStreamChild* aActor)

{

  RefPtr<Runnable> runnable = new MigrateActorRunnable(aActor);

  mThread->Dispatch(runnable, NS_DISPATCH_NORMAL);

}

// nsIEventTarget

NS_IMETHODIMP_(bool)

IPCBlobInputStreamThread::IsOnCurrentThreadInfallible()

{

  return mThread->IsOnCurrentThread();

}

NS_IMETHODIMP

IPCBlobInputStreamThread::IsOnCurrentThread(bool* aRetval)

{

  return mThread->IsOnCurrentThread(aRetval);

}

NS_IMETHODIMP

IPCBlobInputStreamThread::Dispatch(already_AddRefed<nsIRunnable> aRunnable,

                                   uint32_t aFlags)

{

  nsCOMPtr<nsIRunnable> runnable(aRunnable);

  mozilla::StaticMutexAutoLock lock(gIPCBlobThreadMutex);

  if (gShutdownHasStarted) {

    return NS_ERROR_NOT_INITIALIZED;

  }

  return mThread->Dispatch(runnable.forget(), aFlags);

}

NS_IMETHODIMP

IPCBlobInputStreamThread::DispatchFromScript(nsIRunnable* aRunnable,

                                             uint32_t aFlags)

{

  nsCOMPtr<nsIRunnable> runnable(aRunnable);

  return Dispatch(runnable.forget(), aFlags);

}

NS_IMETHODIMP

IPCBlobInputStreamThread::DelayedDispatch(already_AddRefed<nsIRunnable>, uint32_t)

{

  return NS_ERROR_NOT_IMPLEMENTED;

}

} // dom namespace

} // mozilla namespace